A cold front sweeping down from Canada failed to deliver a widespread dusting of snow Monday to the Santa Cruz Mountains, as most of the precipitation moved south to Big Sur.

But it remains cold in the Bay Area, with below-normal temperatures posing a threat to elderly people, pets and plants.

Frigid air blanketed the Bay Area on Monday, with some locations recording overnight low temperatures in the mid-30s, according to the National Weather Service. Sunday evening, the weather service reported a chance of snow in the Santa Cruz Mountains and issued a winter weather advisory, which has since been canceled.

On social media, a few random postings indicated snowfall at a few locations in the Santa Cruz mountains. But it did not snow along Highway 17.

“The amounts that were possible didn’t really materialize,” said Steve Anderson, a meteorologist with the National Weather Service. “The most accumulation was in the Big Sur area. We can see it on satellite, which means it’s probably more than 1 inch.”

The weather service has placed most of the Bay Area under a freeze alert starting Monday at midnight and ending Tuesday at 9 a.m.

Exempt from the freeze alert are San Francisco and the Peninsula south to Mountain View, along with Santa Cruz and Monterey, Anderson said. “It will be cold but not as cold as the other surrounding areas,” he said.

Frost blankets the vegetation in the garden at Lakeside Park in Oakland, Calif., on Tuesday, February 20, 2018. (Laura A. OdaBay Area News Group)

Tuesday morning is expected to deliver the coldest temperatures of the week, with widespread freezing overnight temperatures, according to the weather service. The mercury across much of the region is expected to plunge, with Cloverdale, Calistoga, the East Bay, Morgan Hill and Gilroy seeing temperatures in the high 20s, and San Jose seeing a low around the freezing point of 32 degrees.

The origin of the cold snap — Canada — could be galling for patriotic Americans watching the 2018 winter Olympic Games. By Sunday afternoon, Canada had 16 medals to the United States’ 10. “They’re beating us in the Olympics and now they’re just going to give us some cold air,” Anderson said.

Because the coldest periods will likely last for several hours, plants may die, pets should be brought inside or given appropriate shelter, and older residents could be in danger, Anderson said.

“If you want to check on people you think might be at risk, it’s best to check before nightfall to make sure they’re OK for the morning,” Anderson said.

Compared to average temperatures, the coming days’ highs will be slightly cooler than usual, but night-time and early-morning lows will be up to 10 degrees below normal, Anderson said.

Ethan Baron is a business reporter at The Mercury News, and a native of Silicon Valley before it was Silicon Valley. Baron has worked as a reporter, columnist, editor and photographer in newspapers and magazines for 25 years, covering business, politics, social issues, crime, the environment, outdoor sports, war and humanitarian crises.